As a system for protecting an occupant in the event of a car collision, Japanese Unexamined Patent Application Publication Nos. 2002-79861, 2002-79862, and 2002-145002 describe occupant protection systems in which an inflatable airbag is disposed between a seat cushion and a seat pan and the front of the seat cushion is pushed up by inflating the airbag in a car collision to prevent a so-called submarine phenomenon such that the occupant passes under a lap belt during a front crash even with a seat belt.
The occupant protection systems disclosed in Japanese Unexamined Patent Application Publication Nos. 2002-79861 and 2002-79862 have an inflator in the airbag and a cylindrical diffuser or a rectifier cloth so as to surround the inflator, with which gas from the inflator is diffused or the gas is guided toward the opposite ends of the airbag.
In the occupant protection system disclosed in Japanese Unexamined Patent Application Publication No. 2002-145002, a pipe extending along an airbag is passed through the airbag, in which gas is blown from an inflator disposed outside the airbag through the pipe into the airbag. The pipe has a plurality of gas ports at intervals along the length thereof.
In the conventional occupant protection systems, part of the airbag along the length thereof sometimes inflates early and the other part inflates late.
In the occupant protection systems described in Japanese Unexamined Patent Application Publication Nos. 2002-79861 and 2002-79862, for example, only the vicinity of the gas ports of the diffuser or rectifier cloth probably inflates earlier than the other part.
In the occupant protection system described in Japanese Unexamined Patent Application Publication Nos. 2002-145002, of the gas ports of the pipe, the vicinity of the gas ports adjacent to the inflator probably inflates earlier than the other part.
Accordingly, it is an object of the present invention to provide an occupant protection system in which the problems of the conventional examples are solved so that parts of the airbag along the length inflate substantially at the same time.